Secretion of cytokines, chemokines and antibodies in individuals with resistance to Mycobacterium tuberculosis infection

Cytokines and total antibodies in plasma and supernatants from Quantiferon-TB PLUS assay (Nil and TB1 stimulated) after inclubation for 16-20 hours. Concentrations were measured using luminex assays kits from Biorad (antibody isotyping panel) and Merck-Melliplex (high sensitivity T cell panel) according to manufacturers' instructions. <br> Samples were collected from individuals with latent TB infection (LTBI, IGRA+ &amp; TST+), people with resistance to Mtb infection (Resisters, IGRA- &amp; TST-) and people with discordant results for IGRA and TST (TST=0 and IGRA &gt; 1IU/mL). IGRA+ for IFN-gamma level &gt;0.35IU/mL; IGRA- for IFN-gamma &lt;0.35IU/mL; TST+ for induration &gt;10mm and TST- for induration &lt;10mm